Lubricant additive composed of a mixture of amine salts of monoamides and monoamides of alkenyl succinic acids



United States Patent 3,427,245 LUBRICANT ADDITIVE COMPOSED OF A MIX-TURE 0F AMINE SALTS 0F MONOAMIDES AND MONOAMIDES 0F ALKENYL SUCCINICACIDS Bruce W. Hotten, Orinda, Calif., assignor to Chevron ResearchCompany, San Francisco, Calif., a corporation of Delaware No Drawing.Continuation-impart of application Ser. No. 423,316, Jan. 4, 1965. Thisapplication Aug. 15, 1966, Ser. No. 572,218 U.S. Cl. 252--34.7 ClaimsInt. Cl. C10m J/36, 1/08 ABSTRACT OF THE DISCLOSURE Mixtures ofaliphatic hydrocarbon substituted succinamic acid amine salts, whereinthe amine is a secondary amine, are provided for use under extremecorrosion conditions, particularly phosphate lubricants.

This application is a continuation-in-part of application Ser. No.423,316, filed Ian. 3, 1965, now abandoned.

This invention concerns novel rust inhibitors which provide rustprotection in the presence of phosphate esters. More particularly, thisinvention concerns C-alkenyl substituted succinamic acid salts whichprovide rust protection in the presence of phosphate esters.

The widespread use of metals subject to corrosion, particularly ferrousmetals which are subject to rusting, has encouraged efforts to findmethods to prevent the corrosion. Corrosion can occur in a variety ofenvironments. Rusting is a particular problem with ferrous metals whenwater is present. Rusting can be a problem with containers for corrosivefluids, with bearings or other parts of machinery which must operate inthe presence of water, e.g., steam turbines, or with the moving .partsof engines where water tends to form or collect.

The rusting problem is extremely severe with materials which promote orenhance rusting, such as phosphate esters which are employed ashydraulic fluids and extreme pressure agents, as well as for other uses.With phosphate esters, the problem of rust protection is furtheraggravated, because many of the common commercial rust inhibitors arerelatively or totally ineffective.

Succinic acid, substituted succinic acids and derivatives have found useas corrosion inhibitors. Illustrative of United States patentsdisclosing alkenyl succinic acids or derivatives are US. Patents Nos.2,124,628, 2,133,734, 2,279,688, 2,568,876, 2,604,451, 2,779,740 and2,783,206. Many of the derivatives are concerned with amides or imidesof polyalkylene polyamines or amide esters or alkanolamines.

Pursuant to this invention, the partial amine salts of alkenylsuccinamides are provided, wherein the alkenyl succinic acid from whichthe amide is derived is of from 14 to 25 carbon atoms and the amine fromwhich the amide is derived is a secondary amine having two hydrocarbylgroups of from 1 to 10 carbon atoms and being of a total of from 2 to 20carbon atoms, more usually of from 2 to 16 carbon atoms. (By hydrocarbylis intended a monovalent organic radical composed solely of carbon andhydrogen, which may be aliphatic, alicyclic or aromatic or combinationsthereof, e.g., aralkyl.) Usually, the hydrocarbyl groups will be free ofaliphatic unsaturation, olefinic and acetylenic, particularlyacetylenic.

The amine used for formation of the salt may be the same or differentthan the amine used for formation of the succinamide. The amine used forsalt formation is also secondary, having hydrocarbyl substituents havinga total of from 2 to 20 carbon atoms. The preferred substituents forboth amines (used in the formation of amide and salt) are lower alkyl offrom 1 to 6 carbon atoms, and particularly aryl of from 6 to 10 carbonatoms.

The compounds of this invention have the following formula:

CH2-CHR COX COX wherein R is an aliphatic hydrocarbon group, (free ofacetylenic unsaturation) e.g., alkyl or' alkenyl, of from 10 to 21carbon atoms, one of X and X is an N,N-dihydrocarbyl substituted aminoradical and the other is from 5 to mole percent of amine salt and theremainder hydroxyl.

The compositions of this invention are, therefore, mixtures of (I)CH2CHR wherein R is as defined previously, one of X and X isN,N-dihydrocarbylamino, preferably hydrocarbyl is lower alkyl or aryl,having a total of from 2 to 20 carbon atoms and the other is hydroxyl,and

wherein R is as defined previously and one of X and X isN,N-dihydrocar-bylamino, preferably lower alkyl or aryl, having a totalof from 2 to 20 carbon atoms and the other is wherein R and R arehydrocarbyl groups of from 1 to 10 carbon atoms, preferably lower alkyland aryl, and may be the same or different.

The mole percent of compostiion (I) is 40 to 95, while that of II iscorrespondingly 5 to 60. More usually, the mole percent of (I) will beto 95, with the corresponding amount of II being 5 to 35.

Generally, the aliphatic hydrocarbyl radical of the alkenylsuccinic acidwill not be a single radical, but a mixture of various radicals withinthe carbon range indicated. For example, mixtures having relativelyequal amount of radicals of from 15 to 21 carbon atoms or from 9 to 21carbon atoms find use in this invention.

The alkenyl or alkyl group bonded to the succinyl radical is a normalstraight chain olefinic radical or alkyl radical. That is, the alkenylor alkyl radical is derived from an olefin having all of its carbonsexcept for the terminal carbons bonded to only two other carbons, theterminal carbons being bonded to only one carbon. However, the succinylradical need not be bonded to the 1 carbon of the alkenyl radical,although the 1 position will generally be the position for bonding.

The following is a list of succinamic acids which may be used for theacid-amino salt mixtures of this invention:

N,N-dimethyll n-eicosenylsuccinamic acid N,N-diethyln-tetradecenylsuccinamic acid N,N-diethyl n-pentadecenylsuccinamic acidN,N-diethyl n-octadecenylsuccinamic acid N,N-diethyln-eicosenylsuccinamic acid N,N-dibutyl n-dodecenylsuccinamic acidN,N-dibutyl n-tetradecenylsuccinamic acid N,N-dibutyln-hexadecenylsuccinamic acid N,N-dihexyl n-tetradecenylsuccinamic acidN,N-diphenyl n-dodccenylsuccinamic acid N,N-diphenyln-tetradecenylsuccinamic acid N,N-diphenyl n-hexadecenylsuccinamic acidN,N-diphenyl n-heptadecenylsuccinamic acid N,N-diphenyln-octadecenylsuccinamic acid N,N-ditolyl n-hexadecenylsuccinamic acidN,N-dibenzyl n-tetradecenylsuccinamic acid The alkenyl succinic acidsused in the formation of the succinamic acids are prepared by thereaction of an olefin, preferably an alpha-olefin, with maleic anhydrideto form the alkenyl succinic anhydride. This product may then behydrogenated to form the alkyl succinic anhydride. However, in mostinstances there would be little.

if any advantage in the alkyl over the alkenyl succinic anhydride and,to that extent, the hydrogenation step to the alkyl succinic anhydrideis considered superfluous for the purposes of this invention. Themethods of reacting an olefin with .maleic anhydride are well known inthe art and do not require exemplification; here.

Illustrative of various alpha-olefins which find use are decene-l,undecene-l, dodecene-l, tridecene-l, tetradecene-l, pentadecene-l,hexadecene-l, heptadecene-l, octadecene-l, nonadecene-l, eicosene-l,heneicosene-l.

When preparing the compounds of this invention the desiredalkenylsuccinic anhydride is reacted with a secondary amine having theformula wherein R and R are hydrocarbyl groups of from 1 to carbonatoms, more usually of from 2 to 8 carbon atoms. Preferably R and R arealkyl or carbocyclic aryl. The alkyl groups will generally be of from 2to 6 carbon atoms, while the aryl groups will generally be of from 6 to10 carbon atoms, more usually of from 6 to 8 carbon atoms. The preferredamines used for formation of the salts are the same as those used forpreparation of the amide. Usually, the partial salt is obtained by usingan excess of the amine when preparing the succinamic acid.

Illustrative of various amines are dimethylamine, diethylamine,dipropylamine, dibutylamine, dipentylamine, dihexylamine,diheptylarnine, dioctylamine, dinonylamine, didecylamine,methylhexylamine, ethylbutylamine, methyldecylamine, diphenylamine,ditolyeamine, tert.-butylphenylmethylamine, N-methylaniline,isopropylphenethylamine, benzylmethylarnine, etc. While inertsubstituents may be present in the secondary amine, it is preferred thatthe nitrogen substituents be hydrocarbon.

The amines used may be a single amine or a mixture of amines.

The following examples are offered by way of illustration and not by wayof limitation.

Example A Into a reaction flask in a nitrogen atmosphere was introduced352 g. (1.5 moles) of olefins, derived from cracking wax, in the rangeof from C to C having an average molecular weight of 230, and 147 g.(1.5 moles) of maleic anhydride and the mixture heated for 10 hours at atemperature in the range of about 180-235 C. At the end of this time,the product was cooled and isolated yielding 355 g. Neutralizationequivalent was 216 (Calc. 160) indicating about 70% reaction with theremaining portion being unreacted olefin.

Example B Into a reaction flask in a nitrogen atmosphere was introduced362 g. (1.5 moles) of olefins, derived from cracking wax, having from tocarbon atoms (242 average molecular weight) and 147 g. of maleicanhydride (1.5 moles) and the mixture heated at a temperature of about180-250 C. for a period of 3 hours. At the end of this time, 383 g. of aproduct was isolated. Neutralization equivalent 250 (Calc. 170)indicating about 70% reaction to form the alkenyl succinic anhydride.

Example I Into a reaction flask was introduced 34 g. of the product ofExample B and 7.3 g. of diethylamine (0.1 mole) (47 mole percent excess)and the mixture heated at 50 C. for 1 hour. At the end of this time, thereaction product 'was cooled and the product isolated'Neutralizationequiv:

alent, 343.

- Example III Into a reaction flask was introduced 9.2 g. (0.019 mole)of the product obtained in Example B and 4.68 g. (10% excess) ofdiphenyl amine and the mixture heated at C. The reaction mixture wasallowed to cool and the product isolated.

Example IV Into a reaction flask was introduced 9.2 g. (0.019 mole) ofthe product obtained in Example B and 5.10 g. (20% excess) of diphenylamine and the mixture heated at 150 C. The reaction mixture was allowedto cool and the product isolated.

The products of this invention were tested under a variety of severeconditions to demonstrate their excellence in inhibiting rust formation.

The firs-t tests reported are the turbine oil test ASTM D 665-60 and theEmulsibility Test AST M D 1401-56T, the latter demonstrates the abilityof oil and water to separate from each other. Since it is essential thatthe oil and water separate at a reasonable rate in a turbine, the effectof any additives upon the separation is essential to a determination oftheir aflicacy. The rust test uses both distilled and synthetic seaWater on a standard carbon steel specimen. The following table indicatesresults obtained both as to emulsibility and rusting in distilled wateras well as synthetic sea water. The sample used 0.1 weight percent ofthe succinamic acid in a turbine oil comprising 92% heavy and 8% lightturbine oil base, o,o'-di-t-butylp-cresol antioxidant, 0.3 weightpercent and poly(di- The materials of this invention permit rapidseparation between the oil and water, while providing excellent rustprotection.

Using tricresyl phosphate in place of the turbine oil in the turbine oilrust test described above, the following results were obtained:

TABLE II Rust observed Succmamlc acid Wt. percent Distilled Syntheticwater sea water 0 Heavy rust Heavy rust. 1 Few specks.

4 No rust.

Using 2 weight percent, the composition of Example I was tested in agrease rusting test (ASTM D 1743-60T).

The test is described as a method for determining the corrosionpreventive properties of greases using grease-lubricated tapered rollerbearings stored under wet conditions. This method shows correlationbetween laboratory results and service for grease lubricated aircraftwheel bearings. The grease used was a lithium stearate-bis(2-ethy1-hexyl) sebacate grease. At the end of the test, no rust was observed,giving the grease the high rating of 1.

Finally, the exemplary composition of Example IV, the partial salt ofN,N-diphenylalkenylsuccinamic acid was tested with a variety ofcommercial phosphate ester hydraulic fluids in the Humidity Cabinet Test(ASTM D 1748). The test employs 100% relative humidity and 120 F.temperature. The following table indicates the results:

TABLE III Rust observed in 24 hours Without additive, With 1 wt. psrcentof Ex.

Phosphate ester hydraulic fluid Skydrols=Nonflammable aviation hydraulicfluids-500A is based on dibutyl phenyl phosphate, 7000 is based on octyldiphenyl phosphate. Pydrauls=Nonfiammable industrial hydraulic fluids,based on tricresyl phosphate and chlorinated biphenyl.

The above results demonstrate the extraordinary capability of thecomposition of this invention in protecting ferrous metals from rusting.Not only are the compositions of this invention effective withhydrocarbon materials and fatty acid-salt greases, but they areeffective in the presence of the corrosion promoting phosphate esters.Moreover, while providing corrosion protection in the turbine oil test,they are also capable of passing the emulsibility test, essential totheir usefulness in a turbine.

The compositions of this invention may be used with a wide variety oflubricating media, including oils of lubricating viscosity, as well asgreases. Various base oils which find use include such oils as petroleumlubricating oil: naphthenic base, parafiin base and mixed base;synthetic oils; alkylene polymers and alkylene oxide polymer; esters oforganic and inorganic acids; aryl hydrocarbons and ethers; organicsilicon compounds, etc.

Various grease thickeners include alkali metal and alkaline earth metalcarboxylates, such as lithium hydroxy stearate, complex calcium acetatethickeners, and the sodium salt of tallow acids.

As will be evident to those skilled in the art, various modifications onthis invention can be made or followed, in the light of the foregoingdisclosure and discussion, without departing from the spirit or scope ofthe disclosure or from the scope of the following claims.

I claim:

1. A composition of matter useful under extreme corrosion conditionsresulting from the presence of phosphate containing lubricantsconsisting of a mixture of l C OX 0 OX wherein R is a straight chainaliphatic hydrocarbon group of from 10 to 21 carbon atoms, one of X andX is N,N- dihydrocarbyl-amino having from 2 to carbon atoms, and theother is hydroxyl, and

n om-CH-R wherein R is as defined previously, one of X and X isN,N-dihydrocarbylamino having a total of from 2 to 20 carbon atoms andthe other is wherein R and R are hydrocarbyl groups of from 1 to 10carbon atoms and, wherein the mole percent of (I) is in the range of 40to 95, while the corresponding mole percent of (II) is in the nange of 5to 60.

2. A composition according to claim 1, wherein saidN,N-dihydrocarbylamino is diarylamino, wherein said aryl group is offrom 6 to 10 carbon atoms.

3. A composition according to claim 1, wherein saidN,N-dihydrocarbylamino is di(lower alkyl) amino.

4. A composition according to claim 1, wherein R is a mixture of alkenylgroups of from 9 to 21 carbon atoms.

5. A composition of matter having from 40 to mole percent of CH2 CHRoH-CHR ON(CH.-,)z (50211 I COEH CON(C5H5)2 and correspondingly from 5 to60 mole percent of CO2HNH( aH5)r CH2CHR 3 N( u s)2 C N( a s)2 CH:CHR

O2HNH(Ca 6)1 wherein R is a straight chain alkenyl group of from 10 to21 carbon atoms.

6. In a lubricating oil or grease composition, in an amount which iseffective for inhibiting corrosion, a composition according to claim 5.

7. A method of protecting a surface subject to corrosion which comprisesapplying to said surface an effective amount to inhibit the corrosion ofa composition according to claim 1.

8. In a lubricating oil or grease composition, in an amount which iseifective for inhibiting corrosion, a composition according to claim 1.

9. In a turbine oil or phosphate lubricating composition, in an amountwhich is eifective for inhibiting corrosion, a composition according toclaim 1.

10. A composition according to claim 1, wherein R is terminally attachedto the CH of the succinamic acid.

References Cited UNITED STATES PATIENTS 2,549,270 4/ 1951 Watson252-49.8 2,604,449 7/1952 Bryant et al. 260-534 X 2,604,451 7/ 1952Rocchini 252-515 2,725,359 1/ 1955 Harman et al 252-498 2,779,740 1/1957 Messina 252-515 2,977,309 3/1961 Godfrey et al. 252-515 FOREIGNPATENTS 478,308 7/ 1937 Great Britain.

DANIEL E. WYMAN, Primary Examiner.

W. H. CANNON, Assistant Examiner.

US. Cl. X.R. 252-498, 51.5, 34, 392

